Things to tweet about this week

The new Twitter Music app is expected to launch soon, currently available by invite.

The new Twitter Music app is expected to launch soon, currently available by invite.

By Jessica Galliart, @jessicagalliart

It's hard to keep up with everything floating around about Twitter, Facebook and the like. We know. So here are a few social media noteables to keep tabs on this week.

Twitter music app -- nope, still not out

The new music community app from Twitter launched exclusively to music "influencers"--like Ryan Seacrest? OK ... -- last week on an invite-only basis, and, so far, it sounds promising. According to tech bloggers who have tried it, Twitter Music will have both a web interface and a downloadable app; integrate with YouTube and Vevo; pull in tracks from Spotify, iTunes, Rdio and Soundcloud; include a charts feature from We Are Hunted, the app Twitter recently acquired; and allow for track purchases. No word on when it will be widely available yet: music.twitter.com.

Mailbox app now available to all

Finally! No more waiting in that neverending virtual reservation line. After testing the app's bandwidth for the 10 weeks it has been in the app store on a reservations-only basis, the hyped email app for iPhone is now available for all to download.

You can view a collection of videos uploaded to YouTube that contain footage of the explosions in Boston Monday via the site's "Spotlight" playlists feature. Go to youtube.com/youtube.

Facebook chat heads coming to iOS

Execs said early tuesday that the oddly-named messaging initiative will appear inside the iOS Facebook application as soon as late Tuesday. The "chat heads" allow for in-app chats with friends that, according to Facebook, improves on current mobile messaging capabilities. (Instead of receiving a notification of a new Facebook message, a "chat head" of the person messaging you will pop up.)

Daft Punk Vines new album tracklist

It's coming! The French duo released the tracklist of their anticipated new album, "Random Access Memories," via a six-second Vine video. Yes, all of the tracks sound super sexy. "Memories" is out May 21, so keep an eye out for more teasers on social media in the coming weeks.